500 cc

Hmmm... never thought of that. I think Honda sells a 500cc 4 stroke for the streets.

Do you mean running two, and four strokes together again like they did in 2003(or was it 02')?

If your talking a 500 four stroke, why? They will be replacing the 250's with 600cc's!

You don't keep the same performance with a 37.5% drop in displacement without pretty massive changes elsewhere. Forced induction, rotary engines, etc. could get there, but what's the point?

Well if someone wanted to build a 500cc engine they could as the 800cc is only the max displacement. Illmor ran their 800 at Valencia in the last race for the 990's.

<div class='quotetop'>QUOTE (waterfire @ Mar 28 2008, 09:03 AM) <{POST_SNAPBACK}><div class='quotemain'>Hi

I mean if it's possible to have the same perfomance in a 500cc 4-stroke as in a 800cc 4-stroke. How?? I don't know!! . That's what I am asking .
And that goes for the 250cc and 125cc. If it's possible, somehow, to change them to 4-stroke and keep the same cc's, and keep the same perfomance.

Oh I see your question now ....

No ..... like capacity two strokes are more powerful

There is some conjecture as to just how much more powerful though .... that is where the real debate was still centred, however try as you might ...... it seems it has never been really dealt with in a truly scientific study type manner.

Part of the reason for this is ..... just as the debate was getting serious, another thing came into the equation ........ fuel efficiency ........ even Lassie ( your dog ) can see that the 2 stroke has serious problems in its inherent design that will never make it competitive, in fuel efficiency, with the more positive displacement of a 4 stroke ...... in performance engines ...


So ....... 2 strokes are all but dead ....except:

....... where the primary design criteria is for lots of power needed in a very small package ...... and the fuel efficiency problem is "coped with" eg. chainsaws and brushcutters etc. ( green wise the amount of energy a human expends ( hence has to replace with earth resources ) to carry the extra weight of a 4 stroke surpasses the earth resources used to power the difference 2 stroke .... or the energy to run the brain thinking about it

........ very large ( huge ) low performance spec. ( compared to what is achievable ) diesel engines with very efficient fuel/air mixing systems ...... efficiencies of running huge valve trains comes into it here ...... so the deabate is ..... do I just build a bigger two stroke and inject just enough fule to be near completely burned prioir to the exhaust opening ( and they have extended power strokes as they have mechanical exhaust valves with corresponding loss of any natural crankcase primary charging system ... so they are usually super or turbo charged ..... blah blah blah ...... and the savings is more than it takes 50 chinese shipbuilding engineers brains to run ......


In short ..... No a two stroke of the same "rated" capacity is more powerful. ( But at the cost of efficiency .... seems to be the PC thing to add these days )

<div class='quotetop'>QUOTE (waterfire @ Mar 28 2008, 10:20 AM) <{POST_SNAPBACK}><div class='quotemain'>Thanks for your explanation.
But.. is it possible to make a 500cc 4-stroke as effective as the current 800cc 4-stroke?????


Well the "CC" which is the internal swept capacity of the pistons ( in cubic centimetres ) in the cylinder of an engine, is the part that tells how much space is inside to burn the fuel within ...... if you think about it like a furnace ..... a simillar furnace of the same design but bigger inside will let you put more "burnables" in it .... and will hence have a bigger fire putting out more energy at any given moment ...... so I doubut that they will ever get more or even simillar power out of a 500cc engine with the same design as a say bigger 800cc of that design. Or I doubt that tweaks for "inertia", monetum, weight etc. will ever have such significance anymore....

But with design improvements engines tend to get more powerful ... so maybe the 500cc of tommorrow will be as powerful as the 800cc of today ..... thats how it has allways gone in the past ..... and thats what development is all about

Didn`t Honda try this a long time ago with the oval pistons (not the NR750).It didn`t cut the mustard but now with tech coming on so far it may be viable,I don`t know.

People have run under the maximum capacity limit before, but i was under the impression that was in situations where smaller engines had been bored up for bigger classes. Aprilia used to run a 400 in the 90's, and Honda ran a 300cc bike in the 350 class in the 60's.

<div class='quotetop'>QUOTE (BarryMachine @ Mar 27 2008, 10:53 PM) <{POST_SNAPBACK}><div class='quotemain'>So ....... 2 strokes are all but dead ....

Long live 2 strokes!

Does anyone know of any manufacturer designing a diesel engine motocycle ? Could it happen ? Is it happening ? Could they be the future ?

<div class='quotetop'>QUOTE (Dion @ Apr 14 2008, 08:51 PM) <{POST_SNAPBACK}><div class='quotemain'>Does anyone know of any manufacturer designing a diesel engine motocycle ? Could it happen ? Is it happening ? Could they be the future ?
God I hope not. Diesel - yuk. Think of the sound of 18 of them idling on the grid.

<div class='quotetop'>QUOTE (Dion @ Apr 15 2008, 05:51 AM) <{POST_SNAPBACK}><div class='quotemain'>Does anyone know of any manufacturer designing a diesel engine motocycle ? Could it happen ? Is it happening ? Could they be the future ?


Yes you can already get them .... ssearch Royal Enfield ...India diesel motorcyle

But I must admit i do see it as a way of the future ..... a decently designed deisel is a great engine .... just look at the Audi R10 or what ever its called.


And when spark ignited engines are running ethanol based fuels and diesels running biodiesel .... maybe the diesel with be the better option. ??

Diesels need to be heavier than an equivalent petrol engine to be strong enough to withstand the increase in compression ratio needed to make them more powerfull. This extra weight would be far more of a problem on a bike than in a car.

NO, you cannot build a 500cc as powerful as 800cc using the same technology available. Honda tried to simulate a 2 stroke with the NR 4 stroke and it was a big failure.

There has been a diesel bike, I'm sure I've seen it. but it was a piece of junk. Diesel's are heavier and vibrate much more, not really something you want in a bike. It might happen that a small diesel scooter appears or something like that, but I don't see normal road bikes powered by diesels in the near future.

<div class='quotetop'>QUOTE <div class='quotemain'>QUOTE (Dion @ Apr 14 2008, 08:51 PM)
Does anyone know of any manufacturer designing a diesel engine motocycle ? Could it happen ? Is it happening ? Could they be the future ?

theres loads of diesel motorbikes. the british army use them.

http://en.wikipedia.org/wiki/Diesel_motorcycle

http://www.peace65.freeserve.co.uk/Picture...M1%20spec-3.pdf

<div class='quotetop'>QUOTE (Teomolca @ Apr 15 2008, 09:47 AM) <{POST_SNAPBACK}><div class='quotemain'>NO, you cannot build a 500cc as powerful as 800cc using the same technology available. Honda tried to simulate a 2 stroke with the NR 4 stroke and it was a big failure.

While I agree, the NR500 was built in the early 80's wasn't it? 4 strokes have taken a HUGE leap since then.

I guess we'll see in the laptimes when 400's and 600's replace 125 and 250.